In the field of communications technologies, with the daily increase of radio services, the requirement for the radio data transmission rate becomes higher and higher. The technology demands of International Mobile Telecommunication-Advanced (IMT-Advanced) specify that the future radio communication system needs to be capable of supporting a higher data rate. In order to support high-speed data transmission, the following technical means may be used. On one hand, the frequency spectrum utilization may be improved, for example, the frequency spectrum utilization in the conventional bandwidth may be improved by using high order modulation, a multi-antenna technology, and an Orthogonal Frequency Division Multiplexing (OFDM) technology; on the other hand, the transmission bandwidth of the system may be increased. Taking an LTE-Advanced (LTE-A) system as an example, the maximum transmission bandwidth of the system is 20 MHz, and in order to meet a greater bandwidth demand and be compatible with the conventional third Generation mobile communication system or Long Term Evolution (LTE), many manufacturers propose that a carrier aggregation technology is used in new systems such as LTE-A, so as to meet the requirement of high-speed data transmission. The carrier aggregation technology is to aggregate multiple carriers together in a conventional system, so as to form a higher transmission bandwidth, thereby improving the data transmission rate.
The currently proposed carrier aggregation solutions include continuous carrier aggregation and discontinuous carrier aggregation. In the continuous carrier aggregation, multiple aggregated carriers aggregated together are continuous; and in the discontinuous carrier aggregation, the aggregated carriers are discontinuous. The bandwidths of the multiple aggregated carriers participating in the aggregation may be the same or different, and the bandwidths of the aggregated carriers are all conventional carrier bandwidths of the system. The minimum working bandwidth of the conventional carrier in the system is 1.4 MHz, and the maximum working bandwidth may be up to 20 MHz.
The conventional carrier aggregation technology has at least the following problems. Because each of the multiple aggregated carriers participating in the aggregation has its own synchronization channel, broadcast channel, and baseband processing unit, not only the spectrum resources are consumed, but also the complexity for implementing the system is increased.